Merge pull request #21990 from Microsoft/documentExportAssignment

Document 'ExportAssignment' slightly.

src/compiler/types.ts

@@ -2220,6 +2220,10 @@ namespace ts {
 
     export type ImportOrExportSpecifier = ImportSpecifier | ExportSpecifier;
 
+    /**
+     * This is either an `export =` or an `export default` declaration.
+     * Unless `isExportEquals` is set, this node was parsed as an `export default`.
+     */
     export interface ExportAssignment extends DeclarationStatement {
         kind: SyntaxKind.ExportAssignment;
         parent?: SourceFile;

tests/baselines/reference/api/tsserverlibrary.d.ts

@@ -1412,6 +1412,10 @@ declare namespace ts {
         name: Identifier;
     }
     type ImportOrExportSpecifier = ImportSpecifier | ExportSpecifier;
+    /**
+     * This is either an `export =` or an `export default` declaration.
+     * Unless `isExportEquals` is set, this node was parsed as an `export default`.
+     */
     interface ExportAssignment extends DeclarationStatement {
         kind: SyntaxKind.ExportAssignment;
         parent?: SourceFile;

tests/baselines/reference/api/typescript.d.ts

@@ -1412,6 +1412,10 @@ declare namespace ts {
         name: Identifier;
     }
     type ImportOrExportSpecifier = ImportSpecifier | ExportSpecifier;
+    /**
+     * This is either an `export =` or an `export default` declaration.
+     * Unless `isExportEquals` is set, this node was parsed as an `export default`.
+     */
     interface ExportAssignment extends DeclarationStatement {
         kind: SyntaxKind.ExportAssignment;
         parent?: SourceFile;